Method of producing full arch impressions and sectional tray for use therein at selective quadrants



INVEIIVTORS \MLUAM T. PARKER THOMAS M. COOPER NOV. 3, 1970 w, T. PARKER ETAL METHOD OF PRODUCING FULL ARCH IMPRESSIONS-AND SECTIONAL TRAY FOR USE THEREIN AT SELECTIVE QUADRANTS Filed July 2, 1968 w. Wor

, ATTORNEY United States Patent O 3,537,179 METHOD OF PRODUCING FULL ARCH IM- PRESSIONS AND SECTIONAL TRAY FOR USE THEREIN AT SELECTIVE QUADRANTS William T. Parker and Thomas M. Cooper, Lexington, Ky., assignors, by mesne assignments, to The University of Kentucky Research Foundation, Lexington, Ky., a corporation of Kentucky Filed July 2, 1968, Ser. No. 741,956 Int. Cl. A61c 9/00 US. Cl. 32-17 3 Claims ABSTRACT OF THE DISCLOSURE A method is described for producing a full arch impression by sequentially forming one or more quadrant impressions Within sectional trays and then bonding the sectional trays while in the mouth to an overtray containing the final impression of the remainder of the dental arch thus producing a composite tray which is removed as a unit from the mouth. A rigid sectional tray shell which may be subdivided and adapted for use in any selected quadrant of the arch is provided for use in practicing the method.

BACKGROUND OF THE INVENTION The practice of restorative dentistry has been greatly aided by the availability of modern impression materials, notably those of the type known as rubber-base materials, but for best results such materials require adherence to certain recommended procedures. Among these procedures are the techniques of separate mixing of the smaller amount of material to be emplaced by syringe and the larger amount of material to be emplaced with a tray; the promptness of making the impression after the materials are mixed; the use of a rigid tray; proper distribution of the material to reduce distortion during its polymerization; and the maintaining of the patients mouth in optimum condition for taking of the impression.

When only one side of the dental arch is to be treated, adherence to these requirements is comparatively simple since isolation of the selected portion of the mouth to provide a dry operating field presents no problem. However, when a fixed partial denture or multiple cast restoration is to be accomplished, it is important that a full arch working cast be made so that accurate articulation; provision of optimum occlusal plane and occlusal relationship; and fabrication of a restoration in harmony with the remainder of the dental arch, will be assured.

Although the distinction between the making of a full arch impression wtih a single tray and the making of the same with the sectional tray-over-tray combination, conveniently called piggy-back trays herein, may not at first be apparent, it becomes more evident when the practical difiiculties which are normally encountered by the dentist, are given due consideration. For example, the rubber base impression material does not effectively displace blood, mucous or saliva and thus the preparation of a dry operating field takes time. After one portion of the arch has been prepared in the making of a single impression there is a normal tendency for the tongue and buccal mucosa to displace the injected material while the opposite quadrant is being similarly prepared. The limited effective working time with the rubber base impression material contained in the syringe places an additional limitation on the dentist who is then simultaneously preparing the remainder of the dental arch and avoiding the displacement of the injected material already in position in the first prepared section of the arch, all to the end that a single tray may be used in making a full arch impression. It is a purpose of the present invention to overcome Patented Nov. 3, 1970 SUMMARY OF THE INVENTION In accordance with the invention a rigid arcuate shell in the general shape of the dental arch and having transverse score lines along which the dentist may selectively separate the shell to provide a sectional tray for a given quadrant of the dental arch is used in practicing the method of making full arch impressions of improved accuracy. The method includes the isolation of a selected quadrant of the dental arch followed by placing the sectional tray containing impression material around the teeth in the selected quadrant and thereafter isolating a remaining portion of the dental arch followed by placing an over-tray containing impression material around the teeth in such remaining portion and over the implaced sectional tray. A composite, or piggy-back tray, is formed containing an accurate full arch impression and is removed from the mouth after the impression materials have suitably hardened.

Among the objects of the invention are the provision of an inexpensive sectional tray for use in the method; a combination of sectional tray and over-tray structure of rigid nature which avoids distortion of impression materials contained therein; a method for making accurate full arch impressions; and a method which enables a dentist to avoid limitations on the accuracy of his work as represented by conventional full arch impression fabrication methods.

These and other objects and advantages of the invention will become more apparent as the description proceeds, and when considered in conjunction with the accompanying drawings in which FIG. 1 is a plan view from the underside of an empty sectional tray, prior to being separated into a selected quadrant, and being shown in place within an empty overtray.

FIG. 2 is a sectional view taken on line 22 of FIG. 1.

FIG. 3 is a perspective view showing the top side of a complete sectional tray and indicating score lines of the same.

FIG. 4 is a schematic view of a lower dental arch with one quadrant of the sectional tray in position in the mouth and awaiting the adapting of the over-tray.

FIG. 5 is a sectional view through the sectional trayand taken on line 5-5 of FIG. 4.

FIG. 6 is a schematic view of the full arch impression, and

FIG. 7 is a sectional view through the sectional tray and the over-tray and taken on line 7-7 of FIG. 6.

Referring first to FIG. 3, the sectional tray comprises a rigid shell member having a configuration correspond ing generally to a dental arch and with a generally U- shaped transverse cross-section. This tray, which may be made of any suitable material, preferably plastic, has a series of score lines as indicated at 10 to 13 extending transversely thereof and which may be easily broken by the dentist to provide a portion or portions of the tray as indicated at 14 to 18 corresponding to the quadrant portion of the arch with which such selected portion of the tray is to be used. As used herein the term, score lines is intended to comprise any weakened portion of the shell which will serve to subdivide that shell upon application of bending forces thereto.

The sectional tray is of a configuration suitable for being handled within a conventional full impression tray, such as the Model 400 Sani-tray available from William Getz Corporation, Chicago, 111., and which serves as the over tray in the combination herein disclosed. This over- V p 3 tray has the usual handle 20, proximal and distal walls 21, 22 anda generally-flat top portion 23 with apertures 24 therein and through which impression material squeezes to provide a secure holding action when the composite tray is to be lifted from the mouth.

THE METHOD OF PROVIDING THE FULL ARCH IMPRESSION Upon being provided with a sectional tray and an over-tray as above described, the dentist may practice the invention in accordance with the following procedures. Having determined the quadrant of the arch which is to be treated first, the sectional tray is broken along the corresponding score lines to make available a selected portion such as indicated in FIG. 4. This portion is tried in the patients mouth and the proper path of insertion is noted. The selected tray; portion is then removed, dried, and painted both inside and outwith the appropriate adhesive supplied by the manufacturer of the rubber base impression material which is to be used.

The corresponding quadrant of the patients mouth is then isolated in conventional manner and a dry operating field is prepared. Any gingival retraction which may be necessary is done at this time to insure adequate access to the margins of the teeth prior to injection of the rubber base impression material by syringe at these margins of teeth and gum. The impression material for use in the syringe and the impression material for use with the section tray are then mixed separately, preferably by the dentist mixing one material and an assistant mixing the other. Merely as an example, these materials may comprise the Coe-fiex product available from Coe Laboratories, Inc., Chicago, 111., and which by polymerization will set within the sectional tray in about five minutes after being placed therein. After the material is deposited by syringe at the teeth margins of the isolated quadrant of the mouth, the selected tray portion filled with impression material is then placed over the teeth and ofteeth'37, and these teeth 37. Atthistime, as seen in FIG. 7, some of the impression material squeezes through apertures in the over-tray top 23, and as layer 38 of material is interposed between the over-tray and the sectional tray. This interposed layer as it polymerizes bonds itself both to the'interior of the over-tray and to the exterior of the sectional tray and after a setting period of about 10 minutes a composite tray is formed having a full arch impression as best indicated in FIG. 6.

During removal of the composite, or piggy-back tray from the mouth, a quick vertical force isusedyUpon removal of the composite tray which now contains boundary material at 39, 40 squeezed from the over-tray and disposed outside the impression spaces, a working cast is poured promptly, using conventional techniques and which form no part of the present invention.

It is found that the full arch impressions made in the manner above described are characterized by their improved accuracy. Although the use of a stock rigid sectional tray and a stock rigid over-tray are preferred, it is possible within the broader aspects of the method of the invention and at the cost of additional time on the part of the dentist to make satisfactory composite trays 1 time when the over-tray is placed in the mouth for compressed into place until it stops. Excess impression matetray and the impression which it contains remains in place within the month until the making of the full arch impression is completed.- Having accomplished this important portion of his task, the dentist then tries the over-tray in the mouth noting the portion of the same which will require less filling with impression material due to its overlying the emplaced sectional tray. He then removes the over-tray, dries it, and paints its interior surfaces with adhesive.

The quadrant of the mouth not occupied by the emplaced sectional tray is then isolated using conventional techniques which may employ conventional apparatus as indicated generally at 34, 35, 36 (FIG. 4) to insure a dry operating field. As aboved described, the margins of teeth 37 are treated with another batch of impression material which was made separately from the materials used with the sectional tray. The over-tray meanwhile is suitably filled with another batch of impression material which likewise was mixed separately, care being taken that upon filling the over-traya thinner layer of such material will be :placed therein at the region where it is to overlie the sectional tray. than in the-region where it is to overlie-the. teeth 37. The filled over-tray using the handle for support is then placed in the mouth and pressed into position sothat it covers the emplaced secpleting the full arch impression. The described trays and the method of making full arch impressions therewith are equally suitable for use on the upper or lower dental arches.

What is claimed is:

1. In the practice of restorative dentistry, the method of making full arch impressions comprising, depositing impression material at the margins of teeth in a selected quadrant of the dental arch, promptly placing a rigid sectional tray containing impression material over the teeth and over said deposited material in said selected quadrant and permitting the materials to harden, de-

positing impression material at the margins of other teeth in said dental arch, outside said sectional tray, promptly placing a rigid over-tray containing impression material over said other teeth and the deposited material in contact therewith and over said sectional tray, permitting the impression material in said over-tray to harden and to bond itself to said sectional tray, thereby to form a composite tray containing a full arch impression and thereafter removing said composite tray from the mouth;

2. The method as defined in claim 1 including preparing said sectional tray by coating the inner and outer surfaces of the same with an adhesive prior to adding impression material to said sectional tray.

3. The method as defined in claim 1 including preparing said over-tray by coating the inner surface of the same with an adhesive prior to adding impression material to said over-tray.

References Cited UNITED STATES PATENTS 1,113,090 10/1914 Bell 32l7 2,529,429 11/1950 Spiro 32-17 3,360,860 1/1968 Roland 32- 17 ROBERT PESHOCK, Primary Examiner 

